As described in Patent Document 1 for example, there has been known a segmented grinding wheel wherein a plurality of segmented chips each formed to a predetermined shape by bonding super-abrasive grains such as CBN abrasive grains or the like with vitrified bond are adhered to the circumferential surface of a disc-like core. In the segmented grinding wheel of this kind, after being press-formed and burned, the plurality of segmented chips are arranged on the circumferential surface of a disc-like core made of steel with slight clearances therebetween in the circumferential direction and adhered thereto with a bonding material.
By the way, places for adhesion in the prior art segmented grinding wheel are an internal portion and opposite end portions of each segmented chip, wherein each segmented chip is bonded at its internal portion to the circumferential surface of the disc-like core and is bonded at its opposite end portions to segmented chips next thereto. Then, segmented chips which adjoin at the opposite end portions are mutually jointed to preclude abnormal abrasion of the grinding wheel which would otherwise occur if clearances were provided between the segmented chips.
In segmented grinding wheels, generally, a thermosetting resin such as phenol resin, epoxy resin or the like are used as adhesive. After segmented chips are adhered to the circumferential surface of a disc-like core, the segmented grinding wheel is put into a drying furnace and is dried for a predetermined period of time at a predetermined temperature to set the adhesive.                Patent Document 1: Japanese unexamined, published patent application No. 2003-300165 (paragraph 0024, FIG. 2)        